As is well known, in the last few decades the electronics industry has seen a sea of change in technology. Computers the size of a room have shrunk to the size of a wrist watch. More electronic devices are packed into a smaller space making this revolution possible. This increase in device density has brought with it increase in thermal density, that is, the amount of heat generated per cubic inch.
As is also well known, thermal environment control of a computer or telecommunications equipment has become so critical that a failure in the cooling system can damage the equipment in a matter of minutes. At present, the heat removal from circuits is primarily achieved through air cooling by forced convection over the circuit boards. Air movers such as fans are used in most of the electronic equipment for forced convection.
As is also well known, current fans are configured externally to respond to temperature changes. With such an arrangement, fan voltage is adjusted to correspond to set temperatures. As the voltage is adjusted in response to the sensing of a particular temperature, a corresponding speed, i.e., revolutions per minute (rpm), of a fan results. In some arrangements, fans contain sensors which allow preadjusted temperatures to correspond to preadjusted fan rpms. For example, the detection or sensing of 20.degree. C. may correspond to a fan speed of 1000 rpm, while a sensing of 30.degree. C. may correspond to a fan speed of 2000 rpm.
As is also well known, the relationship of temperature to fan speed may be programmed externally to optimize fan speed. With such an arrangement, a host machine across an interface programs an external controller board, which in turn controls a fan. Using a temperature to fan speed curve, the external controller board controls the rpm of a fan in response to a detected temperature. As is well, known, each of these external controller boards is fan specific, i.e., the host machine programs a specific external fan controller board to control a specific fan. Thus, the host machine can only "talk" or communicate to the fan indirectly, i.e., through the pre-programmed fan-specific external fan controller board. This results in a static relationship between the host and the fan, since information regarding thermal environment gathered by the host machine cannot be imparted on the fan directly. As is well known, standard fans contain only a motor, blades, and a commutation circuit.
What is needed is a field programmable fan which can interface directly with one or more fans and optimize fan performance, i.e., minimize fan noise, minimize power consumption, increase fan longevity, and provide a universal interface between any host machine and fan.